CAN_bus_reader_pub - only read CAN-bus data (not send any data to car)

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Satoshi Nadakiti / Mbed 2 deprecated CAN_bus_reader_pub

only read CAN-bus data (not send any data to car)

SDFileSystem.cpp@0:78752077cc25, 2011-11-09 (annotated)

Committer:: nadakiti
Date:: Wed Nov 09 04:59:01 2011 +0000
Revision:: 0:78752077cc25

Who changed what in which revision?

User	Revision	Line number	New contents of line
nadakiti	0:78752077cc25	1	/* mbed SDFileSystem Library, for providing file access to SD cards
nadakiti	0:78752077cc25	2	* Copyright (c) 2008-2010, sford
nadakiti	0:78752077cc25	3	*
nadakiti	0:78752077cc25	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
nadakiti	0:78752077cc25	5	* of this software and associated documentation files (the "Software"), to deal
nadakiti	0:78752077cc25	6	* in the Software without restriction, including without limitation the rights
nadakiti	0:78752077cc25	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
nadakiti	0:78752077cc25	8	* copies of the Software, and to permit persons to whom the Software is
nadakiti	0:78752077cc25	9	* furnished to do so, subject to the following conditions:
nadakiti	0:78752077cc25	10	*
nadakiti	0:78752077cc25	11	* The above copyright notice and this permission notice shall be included in
nadakiti	0:78752077cc25	12	* all copies or substantial portions of the Software.
nadakiti	0:78752077cc25	13	*
nadakiti	0:78752077cc25	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
nadakiti	0:78752077cc25	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
nadakiti	0:78752077cc25	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
nadakiti	0:78752077cc25	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
nadakiti	0:78752077cc25	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
nadakiti	0:78752077cc25	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
nadakiti	0:78752077cc25	20	* THE SOFTWARE.
nadakiti	0:78752077cc25	21	*/
nadakiti	0:78752077cc25	22
nadakiti	0:78752077cc25	23	/* Introduction
nadakiti	0:78752077cc25	24	* ------------
nadakiti	0:78752077cc25	25	* SD and MMC cards support a number of interfaces, but common to them all
nadakiti	0:78752077cc25	26	* is one based on SPI. This is the one I'm implmenting because it means
nadakiti	0:78752077cc25	27	* it is much more portable even though not so performant, and we already
nadakiti	0:78752077cc25	28	* have the mbed SPI Interface!
nadakiti	0:78752077cc25	29	*
nadakiti	0:78752077cc25	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
nadakiti	0:78752077cc25	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
nadakiti	0:78752077cc25	32	*
nadakiti	0:78752077cc25	33	* SPI Startup
nadakiti	0:78752077cc25	34	* -----------
nadakiti	0:78752077cc25	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
nadakiti	0:78752077cc25	36	* asserting CS low and sending the reset command (CMD0). The card will
nadakiti	0:78752077cc25	37	* respond with a (R1) response.
nadakiti	0:78752077cc25	38	*
nadakiti	0:78752077cc25	39	* CMD8 is optionally sent to determine the voltage range supported, and
nadakiti	0:78752077cc25	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
nadakiti	0:78752077cc25	41	* version 2.x. I'll just ignore this for now.
nadakiti	0:78752077cc25	42	*
nadakiti	0:78752077cc25	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
nadakiti	0:78752077cc25	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
nadakiti	0:78752077cc25	45	*
nadakiti	0:78752077cc25	46	* You should also indicate whether the host supports High Capicity cards,
nadakiti	0:78752077cc25	47	* and check whether the card is high capacity - i'll also ignore this
nadakiti	0:78752077cc25	48	*
nadakiti	0:78752077cc25	49	* SPI Protocol
nadakiti	0:78752077cc25	50	* ------------
nadakiti	0:78752077cc25	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
nadakiti	0:78752077cc25	52	* the host starting every bus transaction by asserting the CS signal low. The
nadakiti	0:78752077cc25	53	* card always responds to commands, data blocks and errors.
nadakiti	0:78752077cc25	54	*
nadakiti	0:78752077cc25	55	* The protocol supports a CRC, but by default it is off (except for the
nadakiti	0:78752077cc25	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
nadakiti	0:78752077cc25	57	* I'll leave the CRC off I think!
nadakiti	0:78752077cc25	58	*
nadakiti	0:78752077cc25	59	* Standard capacity cards have variable data block sizes, whereas High
nadakiti	0:78752077cc25	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
nadakiti	0:78752077cc25	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
nadakiti	0:78752077cc25	62	* This is set with CMD16.
nadakiti	0:78752077cc25	63	*
nadakiti	0:78752077cc25	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
nadakiti	0:78752077cc25	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
nadakiti	0:78752077cc25	66	* the card gets a read command, it responds with a response token, and then
nadakiti	0:78752077cc25	67	* a data token or an error.
nadakiti	0:78752077cc25	68	*
nadakiti	0:78752077cc25	69	* SPI Command Format
nadakiti	0:78752077cc25	70	* ------------------
nadakiti	0:78752077cc25	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
nadakiti	0:78752077cc25	72	*
nadakiti	0:78752077cc25	73	* +---------------+------------+------------+-----------+----------+--------------+
nadakiti	0:78752077cc25	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
nadakiti	0:78752077cc25	75	* +---------------+------------+------------+-----------+----------+--------------+
nadakiti	0:78752077cc25	76	*
nadakiti	0:78752077cc25	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
nadakiti	0:78752077cc25	78	*
nadakiti	0:78752077cc25	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
nadakiti	0:78752077cc25	80	*
nadakiti	0:78752077cc25	81	* SPI Response Format
nadakiti	0:78752077cc25	82	* -------------------
nadakiti	0:78752077cc25	83	* The main response format (R1) is a status byte (normally zero). Key flags:
nadakiti	0:78752077cc25	84	* idle - 1 if the card is in an idle state/initialising
nadakiti	0:78752077cc25	85	* cmd - 1 if an illegal command code was detected
nadakiti	0:78752077cc25	86	*
nadakiti	0:78752077cc25	87	* +-------------------------------------------------+
nadakiti	0:78752077cc25	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
nadakiti	0:78752077cc25	89	* +-------------------------------------------------+
nadakiti	0:78752077cc25	90	*
nadakiti	0:78752077cc25	91	* R1b is the same, except it is followed by a busy signal (zeros) until
nadakiti	0:78752077cc25	92	* the first non-zero byte when it is ready again.
nadakiti	0:78752077cc25	93	*
nadakiti	0:78752077cc25	94	* Data Response Token
nadakiti	0:78752077cc25	95	* -------------------
nadakiti	0:78752077cc25	96	* Every data block written to the card is acknowledged by a byte
nadakiti	0:78752077cc25	97	* response token
nadakiti	0:78752077cc25	98	*
nadakiti	0:78752077cc25	99	* +----------------------+
nadakiti	0:78752077cc25	100	* \| xxx \| 0 \| status \| 1 \|
nadakiti	0:78752077cc25	101	* +----------------------+
nadakiti	0:78752077cc25	102	* 010 - OK!
nadakiti	0:78752077cc25	103	* 101 - CRC Error
nadakiti	0:78752077cc25	104	* 110 - Write Error
nadakiti	0:78752077cc25	105	*
nadakiti	0:78752077cc25	106	* Single Block Read and Write
nadakiti	0:78752077cc25	107	* ---------------------------
nadakiti	0:78752077cc25	108	*
nadakiti	0:78752077cc25	109	* Block transfers have a byte header, followed by the data, followed
nadakiti	0:78752077cc25	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
nadakiti	0:78752077cc25	111	*
nadakiti	0:78752077cc25	112	* +------+---------+---------+- - - -+---------+-----------+----------+
nadakiti	0:78752077cc25	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
nadakiti	0:78752077cc25	114	* +------+---------+---------+- - - -+---------+-----------+----------+
nadakiti	0:78752077cc25	115	*/
nadakiti	0:78752077cc25	116
nadakiti	0:78752077cc25	117	#include "SDFileSystem.h"
nadakiti	0:78752077cc25	118
nadakiti	0:78752077cc25	119	#define SD_COMMAND_TIMEOUT 5000
nadakiti	0:78752077cc25	120
nadakiti	0:78752077cc25	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
nadakiti	0:78752077cc25	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
nadakiti	0:78752077cc25	123	_cs = 1;
nadakiti	0:78752077cc25	124	}
nadakiti	0:78752077cc25	125
nadakiti	0:78752077cc25	126	#define R1_IDLE_STATE (1 << 0)
nadakiti	0:78752077cc25	127	#define R1_ERASE_RESET (1 << 1)
nadakiti	0:78752077cc25	128	#define R1_ILLEGAL_COMMAND (1 << 2)
nadakiti	0:78752077cc25	129	#define R1_COM_CRC_ERROR (1 << 3)
nadakiti	0:78752077cc25	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
nadakiti	0:78752077cc25	131	#define R1_ADDRESS_ERROR (1 << 5)
nadakiti	0:78752077cc25	132	#define R1_PARAMETER_ERROR (1 << 6)
nadakiti	0:78752077cc25	133
nadakiti	0:78752077cc25	134	// Types
nadakiti	0:78752077cc25	135	// - v1.x Standard Capacity
nadakiti	0:78752077cc25	136	// - v2.x Standard Capacity
nadakiti	0:78752077cc25	137	// - v2.x High Capacity
nadakiti	0:78752077cc25	138	// - Not recognised as an SD Card
nadakiti	0:78752077cc25	139
nadakiti	0:78752077cc25	140	#define SDCARD_FAIL 0
nadakiti	0:78752077cc25	141	#define SDCARD_V1 1
nadakiti	0:78752077cc25	142	#define SDCARD_V2 2
nadakiti	0:78752077cc25	143	#define SDCARD_V2HC 3
nadakiti	0:78752077cc25	144
nadakiti	0:78752077cc25	145	int SDFileSystem::initialise_card() {
nadakiti	0:78752077cc25	146	// Set to 100kHz for initialisation, and clock card with cs = 1
nadakiti	0:78752077cc25	147	_spi.frequency(100000);
nadakiti	0:78752077cc25	148	_cs = 1;
nadakiti	0:78752077cc25	149	for(int i=0; i<16; i++) {
nadakiti	0:78752077cc25	150	_spi.write(0xFF);
nadakiti	0:78752077cc25	151	}
nadakiti	0:78752077cc25	152
nadakiti	0:78752077cc25	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
nadakiti	0:78752077cc25	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
nadakiti	0:78752077cc25	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
nadakiti	0:78752077cc25	156	return SDCARD_FAIL;
nadakiti	0:78752077cc25	157	}
nadakiti	0:78752077cc25	158
nadakiti	0:78752077cc25	159	// send CMD8 to determine whther it is ver 2.x
nadakiti	0:78752077cc25	160	int r = _cmd8();
nadakiti	0:78752077cc25	161	if(r == R1_IDLE_STATE) {
nadakiti	0:78752077cc25	162	return initialise_card_v2();
nadakiti	0:78752077cc25	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
nadakiti	0:78752077cc25	164	return initialise_card_v1();
nadakiti	0:78752077cc25	165	} else {
nadakiti	0:78752077cc25	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
nadakiti	0:78752077cc25	167	return SDCARD_FAIL;
nadakiti	0:78752077cc25	168	}
nadakiti	0:78752077cc25	169	}
nadakiti	0:78752077cc25	170
nadakiti	0:78752077cc25	171	int SDFileSystem::initialise_card_v1() {
nadakiti	0:78752077cc25	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
nadakiti	0:78752077cc25	173	_cmd(55, 0);
nadakiti	0:78752077cc25	174	if(_cmd(41, 0) == 0) {
nadakiti	0:78752077cc25	175	return SDCARD_V1;
nadakiti	0:78752077cc25	176	}
nadakiti	0:78752077cc25	177	}
nadakiti	0:78752077cc25	178
nadakiti	0:78752077cc25	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
nadakiti	0:78752077cc25	180	return SDCARD_FAIL;
nadakiti	0:78752077cc25	181	}
nadakiti	0:78752077cc25	182
nadakiti	0:78752077cc25	183	int SDFileSystem::initialise_card_v2() {
nadakiti	0:78752077cc25	184
nadakiti	0:78752077cc25	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
nadakiti	0:78752077cc25	186	_cmd(55, 0);
nadakiti	0:78752077cc25	187	if(_cmd(41, 0) == 0) {
nadakiti	0:78752077cc25	188	_cmd58();
nadakiti	0:78752077cc25	189	return SDCARD_V2;
nadakiti	0:78752077cc25	190	}
nadakiti	0:78752077cc25	191	}
nadakiti	0:78752077cc25	192
nadakiti	0:78752077cc25	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
nadakiti	0:78752077cc25	194	return SDCARD_FAIL;
nadakiti	0:78752077cc25	195	}
nadakiti	0:78752077cc25	196
nadakiti	0:78752077cc25	197	int SDFileSystem::disk_initialize() {
nadakiti	0:78752077cc25	198
nadakiti	0:78752077cc25	199	int i = initialise_card();
nadakiti	0:78752077cc25	200	// printf("init card = %d\n", i);
nadakiti	0:78752077cc25	201	// printf("OK\n");
nadakiti	0:78752077cc25	202
nadakiti	0:78752077cc25	203	_sectors = _sd_sectors();
nadakiti	0:78752077cc25	204
nadakiti	0:78752077cc25	205	// Set block length to 512 (CMD16)
nadakiti	0:78752077cc25	206	if(_cmd(16, 512) != 0) {
nadakiti	0:78752077cc25	207	fprintf(stderr, "Set 512-byte block timed out\n");
nadakiti	0:78752077cc25	208	return 1;
nadakiti	0:78752077cc25	209	}
nadakiti	0:78752077cc25	210
nadakiti	0:78752077cc25	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
nadakiti	0:78752077cc25	212	return 0;
nadakiti	0:78752077cc25	213	}
nadakiti	0:78752077cc25	214
nadakiti	0:78752077cc25	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
nadakiti	0:78752077cc25	216	// set write address for single block (CMD24)
nadakiti	0:78752077cc25	217	if(_cmd(24, block_number * 512) != 0) {
nadakiti	0:78752077cc25	218	return 1;
nadakiti	0:78752077cc25	219	}
nadakiti	0:78752077cc25	220
nadakiti	0:78752077cc25	221	// send the data block
nadakiti	0:78752077cc25	222	_write(buffer, 512);
nadakiti	0:78752077cc25	223	return 0;
nadakiti	0:78752077cc25	224	}
nadakiti	0:78752077cc25	225
nadakiti	0:78752077cc25	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
nadakiti	0:78752077cc25	227	// set read address for single block (CMD17)
nadakiti	0:78752077cc25	228	if(_cmd(17, block_number * 512) != 0) {
nadakiti	0:78752077cc25	229	return 1;
nadakiti	0:78752077cc25	230	}
nadakiti	0:78752077cc25	231
nadakiti	0:78752077cc25	232	// receive the data
nadakiti	0:78752077cc25	233	_read(buffer, 512);
nadakiti	0:78752077cc25	234	return 0;
nadakiti	0:78752077cc25	235	}
nadakiti	0:78752077cc25	236
nadakiti	0:78752077cc25	237	int SDFileSystem::disk_status() { return 0; }
nadakiti	0:78752077cc25	238	int SDFileSystem::disk_sync() { return 0; }
nadakiti	0:78752077cc25	239	int SDFileSystem::disk_sectors() { return _sectors; }
nadakiti	0:78752077cc25	240
nadakiti	0:78752077cc25	241	// PRIVATE FUNCTIONS
nadakiti	0:78752077cc25	242
nadakiti	0:78752077cc25	243	int SDFileSystem::_cmd(int cmd, int arg) {
nadakiti	0:78752077cc25	244	_cs = 0;
nadakiti	0:78752077cc25	245
nadakiti	0:78752077cc25	246	// send a command
nadakiti	0:78752077cc25	247	_spi.write(0x40 \| cmd);
nadakiti	0:78752077cc25	248	_spi.write(arg >> 24);
nadakiti	0:78752077cc25	249	_spi.write(arg >> 16);
nadakiti	0:78752077cc25	250	_spi.write(arg >> 8);
nadakiti	0:78752077cc25	251	_spi.write(arg >> 0);
nadakiti	0:78752077cc25	252	_spi.write(0x95);
nadakiti	0:78752077cc25	253
nadakiti	0:78752077cc25	254	// wait for the repsonse (response[7] == 0)
nadakiti	0:78752077cc25	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
nadakiti	0:78752077cc25	256	int response = _spi.write(0xFF);
nadakiti	0:78752077cc25	257	if(!(response & 0x80)) {
nadakiti	0:78752077cc25	258	_cs = 1;
nadakiti	0:78752077cc25	259	_spi.write(0xFF);
nadakiti	0:78752077cc25	260	return response;
nadakiti	0:78752077cc25	261	}
nadakiti	0:78752077cc25	262	}
nadakiti	0:78752077cc25	263	_cs = 1;
nadakiti	0:78752077cc25	264	_spi.write(0xFF);
nadakiti	0:78752077cc25	265	return -1; // timeout
nadakiti	0:78752077cc25	266	}
nadakiti	0:78752077cc25	267	int SDFileSystem::_cmdx(int cmd, int arg) {
nadakiti	0:78752077cc25	268	_cs = 0;
nadakiti	0:78752077cc25	269
nadakiti	0:78752077cc25	270	// send a command
nadakiti	0:78752077cc25	271	_spi.write(0x40 \| cmd);
nadakiti	0:78752077cc25	272	_spi.write(arg >> 24);
nadakiti	0:78752077cc25	273	_spi.write(arg >> 16);
nadakiti	0:78752077cc25	274	_spi.write(arg >> 8);
nadakiti	0:78752077cc25	275	_spi.write(arg >> 0);
nadakiti	0:78752077cc25	276	_spi.write(0x95);
nadakiti	0:78752077cc25	277
nadakiti	0:78752077cc25	278	// wait for the repsonse (response[7] == 0)
nadakiti	0:78752077cc25	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
nadakiti	0:78752077cc25	280	int response = _spi.write(0xFF);
nadakiti	0:78752077cc25	281	if(!(response & 0x80)) {
nadakiti	0:78752077cc25	282	return response;
nadakiti	0:78752077cc25	283	}
nadakiti	0:78752077cc25	284	}
nadakiti	0:78752077cc25	285	_cs = 1;
nadakiti	0:78752077cc25	286	_spi.write(0xFF);
nadakiti	0:78752077cc25	287	return -1; // timeout
nadakiti	0:78752077cc25	288	}
nadakiti	0:78752077cc25	289
nadakiti	0:78752077cc25	290
nadakiti	0:78752077cc25	291	int SDFileSystem::_cmd58() {
nadakiti	0:78752077cc25	292	_cs = 0;
nadakiti	0:78752077cc25	293	int arg = 0;
nadakiti	0:78752077cc25	294
nadakiti	0:78752077cc25	295	// send a command
nadakiti	0:78752077cc25	296	_spi.write(0x40 \| 58);
nadakiti	0:78752077cc25	297	_spi.write(arg >> 24);
nadakiti	0:78752077cc25	298	_spi.write(arg >> 16);
nadakiti	0:78752077cc25	299	_spi.write(arg >> 8);
nadakiti	0:78752077cc25	300	_spi.write(arg >> 0);
nadakiti	0:78752077cc25	301	_spi.write(0x95);
nadakiti	0:78752077cc25	302
nadakiti	0:78752077cc25	303	// wait for the repsonse (response[7] == 0)
nadakiti	0:78752077cc25	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
nadakiti	0:78752077cc25	305	int response = _spi.write(0xFF);
nadakiti	0:78752077cc25	306	if(!(response & 0x80)) {
nadakiti	0:78752077cc25	307	int ocr = _spi.write(0xFF) << 24;
nadakiti	0:78752077cc25	308	ocr \|= _spi.write(0xFF) << 16;
nadakiti	0:78752077cc25	309	ocr \|= _spi.write(0xFF) << 8;
nadakiti	0:78752077cc25	310	ocr \|= _spi.write(0xFF) << 0;
nadakiti	0:78752077cc25	311	// printf("OCR = 0x%08X\n", ocr);
nadakiti	0:78752077cc25	312	_cs = 1;
nadakiti	0:78752077cc25	313	_spi.write(0xFF);
nadakiti	0:78752077cc25	314	return response;
nadakiti	0:78752077cc25	315	}
nadakiti	0:78752077cc25	316	}
nadakiti	0:78752077cc25	317	_cs = 1;
nadakiti	0:78752077cc25	318	_spi.write(0xFF);
nadakiti	0:78752077cc25	319	return -1; // timeout
nadakiti	0:78752077cc25	320	}
nadakiti	0:78752077cc25	321
nadakiti	0:78752077cc25	322	int SDFileSystem::_cmd8() {
nadakiti	0:78752077cc25	323	_cs = 0;
nadakiti	0:78752077cc25	324
nadakiti	0:78752077cc25	325	// send a command
nadakiti	0:78752077cc25	326	_spi.write(0x40 \| 8); // CMD8
nadakiti	0:78752077cc25	327	_spi.write(0x00); // reserved
nadakiti	0:78752077cc25	328	_spi.write(0x00); // reserved
nadakiti	0:78752077cc25	329	_spi.write(0x01); // 3.3v
nadakiti	0:78752077cc25	330	_spi.write(0xAA); // check pattern
nadakiti	0:78752077cc25	331	_spi.write(0x87); // crc
nadakiti	0:78752077cc25	332
nadakiti	0:78752077cc25	333	// wait for the repsonse (response[7] == 0)
nadakiti	0:78752077cc25	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
nadakiti	0:78752077cc25	335	char response[5];
nadakiti	0:78752077cc25	336	response[0] = _spi.write(0xFF);
nadakiti	0:78752077cc25	337	if(!(response[0] & 0x80)) {
nadakiti	0:78752077cc25	338	for(int j=1; j<5; j++) {
nadakiti	0:78752077cc25	339	response[i] = _spi.write(0xFF);
nadakiti	0:78752077cc25	340	}
nadakiti	0:78752077cc25	341	_cs = 1;
nadakiti	0:78752077cc25	342	_spi.write(0xFF);
nadakiti	0:78752077cc25	343	return response[0];
nadakiti	0:78752077cc25	344	}
nadakiti	0:78752077cc25	345	}
nadakiti	0:78752077cc25	346	_cs = 1;
nadakiti	0:78752077cc25	347	_spi.write(0xFF);
nadakiti	0:78752077cc25	348	return -1; // timeout
nadakiti	0:78752077cc25	349	}
nadakiti	0:78752077cc25	350
nadakiti	0:78752077cc25	351	int SDFileSystem::_read(char *buffer, int length) {
nadakiti	0:78752077cc25	352	_cs = 0;
nadakiti	0:78752077cc25	353
nadakiti	0:78752077cc25	354	// read until start byte (0xFF)
nadakiti	0:78752077cc25	355	while(_spi.write(0xFF) != 0xFE);
nadakiti	0:78752077cc25	356
nadakiti	0:78752077cc25	357	// read data
nadakiti	0:78752077cc25	358	for(int i=0; i<length; i++) {
nadakiti	0:78752077cc25	359	buffer[i] = _spi.write(0xFF);
nadakiti	0:78752077cc25	360	}
nadakiti	0:78752077cc25	361	_spi.write(0xFF); // checksum
nadakiti	0:78752077cc25	362	_spi.write(0xFF);
nadakiti	0:78752077cc25	363
nadakiti	0:78752077cc25	364	_cs = 1;
nadakiti	0:78752077cc25	365	_spi.write(0xFF);
nadakiti	0:78752077cc25	366	return 0;
nadakiti	0:78752077cc25	367	}
nadakiti	0:78752077cc25	368
nadakiti	0:78752077cc25	369	int SDFileSystem::_write(const char *buffer, int length) {
nadakiti	0:78752077cc25	370	_cs = 0;
nadakiti	0:78752077cc25	371
nadakiti	0:78752077cc25	372	// indicate start of block
nadakiti	0:78752077cc25	373	_spi.write(0xFE);
nadakiti	0:78752077cc25	374
nadakiti	0:78752077cc25	375	// write the data
nadakiti	0:78752077cc25	376	for(int i=0; i<length; i++) {
nadakiti	0:78752077cc25	377	_spi.write(buffer[i]);
nadakiti	0:78752077cc25	378	}
nadakiti	0:78752077cc25	379
nadakiti	0:78752077cc25	380	// write the checksum
nadakiti	0:78752077cc25	381	_spi.write(0xFF);
nadakiti	0:78752077cc25	382	_spi.write(0xFF);
nadakiti	0:78752077cc25	383
nadakiti	0:78752077cc25	384	// check the repsonse token
nadakiti	0:78752077cc25	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
nadakiti	0:78752077cc25	386	_cs = 1;
nadakiti	0:78752077cc25	387	_spi.write(0xFF);
nadakiti	0:78752077cc25	388	return 1;
nadakiti	0:78752077cc25	389	}
nadakiti	0:78752077cc25	390
nadakiti	0:78752077cc25	391	// wait for write to finish
nadakiti	0:78752077cc25	392	while(_spi.write(0xFF) == 0);
nadakiti	0:78752077cc25	393
nadakiti	0:78752077cc25	394	_cs = 1;
nadakiti	0:78752077cc25	395	_spi.write(0xFF);
nadakiti	0:78752077cc25	396	return 0;
nadakiti	0:78752077cc25	397	}
nadakiti	0:78752077cc25	398
nadakiti	0:78752077cc25	399	static int ext_bits(char *data, int msb, int lsb) {
nadakiti	0:78752077cc25	400	int bits = 0;
nadakiti	0:78752077cc25	401	int size = 1 + msb - lsb;
nadakiti	0:78752077cc25	402	for(int i=0; i<size; i++) {
nadakiti	0:78752077cc25	403	int position = lsb + i;
nadakiti	0:78752077cc25	404	int byte = 15 - (position >> 3);
nadakiti	0:78752077cc25	405	int bit = position & 0x7;
nadakiti	0:78752077cc25	406	int value = (data[byte] >> bit) & 1;
nadakiti	0:78752077cc25	407	bits \|= value << i;
nadakiti	0:78752077cc25	408	}
nadakiti	0:78752077cc25	409	return bits;
nadakiti	0:78752077cc25	410	}
nadakiti	0:78752077cc25	411
nadakiti	0:78752077cc25	412	int SDFileSystem::_sd_sectors() {
nadakiti	0:78752077cc25	413
nadakiti	0:78752077cc25	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
nadakiti	0:78752077cc25	415	if(_cmdx(9, 0) != 0) {
nadakiti	0:78752077cc25	416	fprintf(stderr, "Didn't get a response from the disk\n");
nadakiti	0:78752077cc25	417	return 0;
nadakiti	0:78752077cc25	418	}
nadakiti	0:78752077cc25	419
nadakiti	0:78752077cc25	420	char csd[16];
nadakiti	0:78752077cc25	421	if(_read(csd, 16) != 0) {
nadakiti	0:78752077cc25	422	fprintf(stderr, "Couldn't read csd response from disk\n");
nadakiti	0:78752077cc25	423	return 0;
nadakiti	0:78752077cc25	424	}
nadakiti	0:78752077cc25	425
nadakiti	0:78752077cc25	426	// csd_structure : csd[127:126]
nadakiti	0:78752077cc25	427	// c_size : csd[73:62]
nadakiti	0:78752077cc25	428	// c_size_mult : csd[49:47]
nadakiti	0:78752077cc25	429	// read_bl_len : csd[83:80] - the maximum read block length
nadakiti	0:78752077cc25	430
nadakiti	0:78752077cc25	431	int csd_structure = ext_bits(csd, 127, 126);
nadakiti	0:78752077cc25	432	int c_size = ext_bits(csd, 73, 62);
nadakiti	0:78752077cc25	433	int c_size_mult = ext_bits(csd, 49, 47);
nadakiti	0:78752077cc25	434	int read_bl_len = ext_bits(csd, 83, 80);
nadakiti	0:78752077cc25	435
nadakiti	0:78752077cc25	436	// printf("CSD_STRUCT = %d\n", csd_structure);
nadakiti	0:78752077cc25	437
nadakiti	0:78752077cc25	438	if(csd_structure != 0) {
nadakiti	0:78752077cc25	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
nadakiti	0:78752077cc25	440	return 0;
nadakiti	0:78752077cc25	441	}
nadakiti	0:78752077cc25	442
nadakiti	0:78752077cc25	443	// memory capacity = BLOCKNR * BLOCK_LEN
nadakiti	0:78752077cc25	444	// where
nadakiti	0:78752077cc25	445	// BLOCKNR = (C_SIZE+1) * MULT
nadakiti	0:78752077cc25	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
nadakiti	0:78752077cc25	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
nadakiti	0:78752077cc25	448
nadakiti	0:78752077cc25	449	int block_len = 1 << read_bl_len;
nadakiti	0:78752077cc25	450	int mult = 1 << (c_size_mult + 2);
nadakiti	0:78752077cc25	451	int blocknr = (c_size + 1) * mult;
nadakiti	0:78752077cc25	452	int capacity = blocknr * block_len;
nadakiti	0:78752077cc25	453
nadakiti	0:78752077cc25	454	int blocks = capacity / 512;
nadakiti	0:78752077cc25	455
nadakiti	0:78752077cc25	456	return blocks;
nadakiti	0:78752077cc25	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	09 Nov 2011
Imports:	420
Forks:	1
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	26

SDFileSystem.cpp@0:78752077cc25, 2011-11-09 (annotated)

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